Process for the removal of acid from nitrated starch



Aug. 16, 1938. J. HELLE ET AL 2,127,360

' PROCESS FOR THE REMOVAL OF ACID FROM NI'IRATED STARCH Filed Nov. 10,1956 4 Sheats-Sheet 1 A TrMM/EY Aug. 16, 1938. J. HELLE ET AL 2,127,360-

PRQCESS FOR THE REMOVAL: OF ACID FROM NITRATED. STARCH Filed NOV. 10,1936 4 Sheets-Sheet 2 Aug. 16, 1938.

J. HE'LLE Er AL 2,127,360

PROCESS FOR THE REMOVAL OF ACID FRQMNITRATED STARCH Filed Nov. 10, 19364 Sheets-Sheet 3 2g 1% BY W a? 9mm ATTORNE Y Aug. 16, 1938. J.-HELLEETAL21 36 PROCESS FOR THE REMOVAL OF ACID FROM NITRATED STARCH Filed Nov.10, 1936 4 sheets -sheet 4 MM v W Wz2w ATTb/VNE) Patented Aug. 16, 1938PATENT OFFICE PROCESS FOR THE REMOVAL OF ACID FROM NITRATED STARCHJohann Belle and Alfons Kunz, Fuzfo, Hungary,

assignors to Nitrokemia Ipartelepek Reszvenytarsasag, Budapest, HungaryApplication November 10, 1936, Serial No. 110,187 In Hungary May 22,1936 3 Claims.

This invention relates to a process for the removal of acid fromnitrated starch.

The invention provides means for a continuous operation in aparticularly economic manner, so

5 that the acid removed from the mass can be used again in furtheroperations.

It is known to remove the free mixed acid from nitrated starch bycovering a layer of the nitrated starch of approximately uniform thickwmess with a mineral acid of the same specific gravity, and in the sameamount as the mixed acid contained in the mass, and thereby displacingthe mixed acid in the mass. The displaced mixed acid is freed from waterand can'be used in again as concentrated acid. Themineral acid, forexample sulphuric acid, contained in the mass after displacement of themixed acid is then replaced by water, and thereupon the mass is washed.This procedure isdiflicult to carry out ti) in a, continuous operation,and uses up a considerable amount of acid.

The invention provides a process for overcoming the above mentioneddimculties, and the nitrated starch is arranged in separate batches esin a series, and these batches are treated in coun tercurrent with waterand freed from the mixed acid. The separate masses of nitrated starchidentical one with the other are spread in layers of the same thicknesson filter stones arranged ccseparately one from the other in a commoncarrier, and washed out with water in such a manner that the pure wateris conducted to the mass already repeatedly extractedand containing theleast amount of mixed acid and the acidified water obtained at thispoint is successively conducted to nitro starch masses containing moreand more mixed acid. The aqueous acid drawn from the last mass of theseries is removed and can be used as concentrated acid, for example, 40in nitrating fresh starch. If the nitro starch from which the acid hasbeen extracted is removed for further operations and replaced by acorresponding amountof crude nitrated starch, the removal of acid canproceed without inter- 45 ruption of the operation but before replacingthe washed out nitro starch with a fresh batch of acid-containing nitrostarch the filter stone on which the latter is to be placed must firstbe freed from water, for example, in the manner as hereinafter to bedescribed.

The apparatus in accordance withthis invention is constructed forcontinuous operation. The invention will now be further explained byreference to the accompanying drawings in 55Xwhich:

Fig. 1 is a plan showing particularly the driving means.

Fig. 1a. is a plan view of a portion of Fig. 1.

Fig. 2 is a detail of Fig. 1.

Fig. 3 is a longitudinal section on the line III-III of Fig. 1.

Fig. 4 is a. plan of the attachment.

Fig. 5 shows on an enlarged scale the purification arrangement of theattachment.

Fig. 6' shows a section on the line Vii-VI of Fi 5.

7 shows a section on the line VII-XII of Fig.

Fig. 8 shows the acid delivery to the separate cells.

Fig. 9 shows the arrangement for conducting the, nitrated starch to theattachment.

Corresponding parts inthe drawings are indicated by similar referencenumerals.

The perpendicularly disposed shaft Iii is drivw en by the shaft it bymeans of the bevel searing it and it. The shaft it rotatesintermittently and is operated in this manner by the electric motor itthrough the cooperating drive shown in Fig. 1. The motor it drives theshaft it by means of the spindle it and worm gear H. An eccentric it iskeyed on to the shaftllll and supports therod ii by means oi the roller2%. The rod ii is rotatably mounted on the pivot 22 and is loaded withthe weight it so at its free end.

The rod ti carries a co-operating pawl tilt which engages in the teethof the cog it and turns the shaft 112 through an angular distance equalto the pitch of the said teeth with each 35.

rotation of the eccentric.

At the upper end of the shaft ii an attachment ill is firmly keyedthereto so that this part ll moves with the shaft ii. The attachmentmade, for example of acid resisting steel carries so on its uppersurface a series of segment shaped openings arranged in a circle onebeside the other into which openings filter stones ididbd are fitted tomake a close fit. Under the filter stones 28l3i|3 hollow spaces 29 areprovided in the interior of the attachment each of which hollow spacesopen into a channel 3d also in the interior of the attachment. The loweropenings M of all these channels lie on a horizontally arranged annularsliding surface 32 of the attach ment on which the attachment slides onan edge 33 also forming a sliding. surface of a circular shaped member35. Slots 342-350 are out along the entire sliding surface 35 whichslots are of different lengths for a purpose which will be here- 'member35 is firmly pressed against the sliding surface 02 of the attachment bymeans of a numher of springs 31 so that the wearing of the slidingsurfaces can cause no leakage between the contacting surfaces. The lowerends of the springs 31 abut on the fixed housing 38 of the shaft ll.

A frame 39 having four pyramidal sides lies on each of the filter stonesIll-403. This pyramidal form serves the purpose of preventing the filtercake being carried up with the frame when the latter is raised.

Each frame 39 is attached to an arm 40, all

the arms 40 turning ona ring of pivots ll. A ring 42 is fixed on theattachment between the frames 89 and the pivots I, and the upper edge 43of the ring is slanted outwardly and provided with a swallow tail groove44 for each of the arms 40;

- These grooves form guides for the arms ll in order to prevent sidedisplacement by bending at the pivots ll, when the arms 40 are raisedabove or lowered to the filter stone.

The rollers 45 are arranged on the arms III to guide the latter on tothe edge of the grooves 44.

An arcuate rib ll is arranged as a fixed rail on a part of the circularpath and the height of this rib, which does not rotate with theattachment increases progressively from one end until the height shownin Fig. 3 is reached for the purpose of raising the arm 40 at adetermined position of its path from the filter stone to which itbelongs, and then lowering it again to the same filter stone.

brushes Ii fixed on an endless chain I0. The

chains move over rollers l2, 53, of which I! revolves loosely and II isfixed on to the shaft The shaft It drives the screw conveyor 48 througha worm gear 85 and also drives through helical screw gear I, It, theconical brush l1 which cleans the downwardly bent edge ll of theattachment. All three cleaning devices move the material into thecontainer II.

The material to be treated is conducted from the container II to theseparate cells formed by each filter stone and frame.

The container N is in the form of a funnel, and its lower wide openingII is closed by'a ball valve 62. The valve If is connected with one endof the lever N movable about the pivot 88, and is operated by means ofthe draw rod I.

For this purpose the draw rod OI is'connected with the arm I of a triplelever. the second arm 61 of which through the rod II is in hingedconnection with the beam ll movable about the p vot ll.

The lever ll carries at its free end a roller Ill. The weight II-fixedon to the third arm II of the triple lever presses on the one hand bymeans of the rod I! and the lever M the valve 02 into its seating, andon the other hand by means of the lever 01 and the rod II the roller Illagainst the i MWMMWWMWWMMMMMW cam disc I4 arranged on the hollowshaftIt. The hollow shaft 18 coaxial with the shaft I! is driven by the shaftis of the worm drive l1 and the chain It and chain wheels II and l1.

7 These transmissions are so selected that the hollow shaft 1; and thecam disc I4 arranged thereon together with abutment II makes onerevolution whilst the pawl 25 turns the shafts l2 and I I through a partof a rotation corresponding to the pitch of the teeth.

The number of teeth of the wheel I! is the same as the number of filterstones of the attachment 21, so that with each rotation of the eccentricI! the attachment 21 is rotated through an angular distance equivalentto the pitch of the stones and then remains stationary for a certaintime. The abutment I8 is so arranged that it operates the rods 08 and Mof the valve 02, that is to say. opens and closes the valve 02 duringthe time that the attachment 21 stands still.

The form of apparatus shown in the drawings is adapted for washingnitrated starch. The acids employed for this purpose of differentconcentration are conducted to the containers "-4. arranged on thehorizontal axle II. The containers are of triangular longitudinalsection (see Fig. 8) and the common axle ll is passed through thelowestcorner. Each container lies inside one of the fixed containers"-48, and each of these containers opens at its' lowest piaint into oneof the pipes Hit-Hit. Each of the tubes has a straight extended endprovided with holes 81, and directed radially to the shaft ll, so thatwhen the attachment stands still it is positioned in the middle of oneof the framu N.

The axle I! is mounted in bearings 08 and II and is connected by leverI! and rod II with a triple lever ll, loaded at its other end by theweight I". The triple lever is movable about the fixed axle Ill, and itst d arm III is connected with the lever III mova le about the axle I" bymeans of the rod I II. The lever I" is provided with a roller Illwhichrolls on the periphery of the cam I01, and is operated by theabutment I".

In washing nitrated starch the apparatus is operated as follows:

A reduced pressure isset up in the conduits iii-2" each of which opensinto a special collecting vessel, not shown in the drawings. Thepulplike nitrated starch is conducted to the container in amountsdetermined beforehand. The container Iii is filled with concentratedsulphuric acid, containers "-4! with nitric-sulphuric acid solutions. ofprogressively lower concentration and the containers Q4, II and II withwater. The filling of the containers is efi'ected each time before theattachment is moved on through a subdivision, that is to say over one ofthe frames 30. Conveniently conduits H! are provided for feeding theseveral containers in batches.

First of all the valve 02 is opened by the projection It, by theoperation of the rods I1, I, 85 and 84, as the lower opening SI of thecontainer N is very wide. it empties itself suddenly and its contentsare poured over the filter stone Ill standing under the container It.The pulplike mass suddenly poured on the stone distributes itself on"the stone in the frame standing above it in a layer of uniformthickness.

Simultaneously the projection Ill operates the rods III, ill, II, II, I!and turns the axle 1! in the direction of the arrow Ill so that thecontents of all the containers "-4! are poured respectively into thefunnels 80-08, and through the tubes Ill-Ill to trickle between each twomovements through their fine boreholes 91 on to the filtered nitratedstarch cakes standing under the tube ends. The acid or water so con--ducted to the layers of nitro starch forms thereon layers of liquid ofthe same depth above each.

Concentrated sulphuric acid flows, from the container 89 on to the emptystone 282, and is drawn therethrough by the vacuum under the stone. Theobject of this operation is to free the stone 282 from the water itcontains. This acid is sucked off while the stone is in the positionimmediately following, that is to say where in the drawings (Fig. 4)vthestone 283 is standing.

The channels under the stones 282 and 283 open in the position shown inthe drawings, through the slot 359 of the circular body 35 into thecommon flexible conduit 38L The acid here drawn off is regenerated.

The fresh mass of nitrated starch falling from the containers 69 comesto the stone 28L It contains still a considerable amount of acid, whichis drawn off by the vacuum under the stone,

partly in this position, and partly in the two positions immediatelyfollowing this suction, filtration of the starch occurs simultaneouslyon stones 284- and 289. The channels 99 under the stones 28l, 284, and285 open in the position of the attachment shown in the, drawingsthrough slot 342 of the annular body 39 into the flexible conduit 382corresponding to this slot. The concentrated acid here drawn off isregenerated and used for nitrating fresh starch.

The acid from the container 8| is poured on to the nitrated starch lyingon stone 299. This acid has been drawn from the material on stones 289,299 and 2!. The suction filtering is effected in the three'succeedingpositions 289, 281 and 288 throughthe slot 393 and the tube 393. Theacid drawn of! here is regenerated and used for nitrating fresh starch.

The more dilute acid from container 92 which' which is drawn from thematerial onstones 296-2 98 is conducted to filter stone 292. Suctionfiltration goes on in the three succeeding positions 292,293 and 294 andthe liquid is conducted through the slot 399 of the annulus 39 common tothese positions, and through the flexible-tube 395 and the container 82to the stone 299.

Pure water flows from the container 94 on to the material on stone 299.Suction filtration goes on in both succeeding positions 295 and 298, andthe liquid. drawn off goes through the s1ot346 into the flexible tubing369. It is then conducted to container 83 from where it goes to thestone 292.

In the same way pure water flows from the container 85 on to thematerial on filter stone 291. Suction filtration goes on in the twosucceeding positions 291 and 298 through the slot 391 and tube 381 andthe liquid drawn oil is conducted to the container 83. r

' The material on stone 299 receives pure water from containers 99 whichis drawn of! in positions 299 and 399 through the slot 898 and the tube399.

From the position 399 onwards the frames 39 are raised by therib 49 sothat the material can be removed by the conveyor devices 48 and Si.These conveyor devices remove the material freed from acid to thecontainer 59 and simultaneously the edge of the attachment is cleaned bythe brush'i'l. Water is drawn from the stone coming from the cleaningdevices, through the slot 359 and the tubes 39! and 319.

The above description is given as if the apparatus were at rest, but asit is moving step by step this order of procedure is repeated at eachmovement forward of the attachment so that continually a stone iscovered with fresh nitrated starch, and with the exception of thosestanding under the cleaning devices, acidof the described differentconcentrations or water is conducted to the remainder.

The water required for the process as described is about 0.7 kilo perkilo of nitro starch.

We claim:- I

1. A process for the removal of nitrating acid from nitrated starch bydisplacement of the acid with water, which consists in drawing the watersuccessively through a series of batches of the nitrated starch onfilters wherein the liquid drawn through the last filter of the seriesis passed into the next preceding filter and so on, until the acidremoved from the successively filtered batches of the series is drawnthrough a filter containing fresh nitrated starch, the waterwashednitrated starch being withdrawn from that end of the series where thefresh water enters while the filter thus cleared before'being chargedagain with nitrated starch is freed from water. I

2. A process for the removal of nitrating acid I from nitrated starch bydisplacement of the acid with water, which consists in drawing the watersuccessively through a series of batches of the nitrated starch onfilters wherein theliquid drawn through the last filter of the series ispassed into the next preceding filter and so on, until the acid removedfrom the successively, filtered batches of the seriesxis drawn through afilter containing fresh nitrated starch, the water washed nitratedstarch being withdrawn from that end of the series where the fresh waterenters while the filter thus cleared before being charged again withnitrated starch is freed from water by displacing the water in thefilter with a constituent acid of the nitrating acid.

3. A process for the removal of nitrating acid that end of the serieswhere the fresh water ALFONS xrmz. JOHANN mm.

